Multichip Modules (MCMs) are well known. A typical MCM includes a plurality of diverse elements disposed on one or more substrates enclosed within a molded housing. The diverse elements form an electronic circuit for, for example, driving a motor. Such circuits often include power semiconductor devices which may be connected to one another in a variety of ways.
A conventional circuit arrangement for driving a motor is known as a half-bridge. A half-bridge arrangement includes two power semiconductor devices connected in series. A typical power semiconductor device used in a half-bridge arrangement is a MOSFET, although other power semiconductor devices may also be used.
FIG. 1 shows a half-bridge arrangement using a pair of series-connected MOSFETs 10, 12. As shown in FIG. 1, the source electrode of MOSFET 10 is electrically connected to the drain electrode of MOSFET 12. In this configuration, input voltage Vin is connected to the drain electrode of MOSFET 10 while the source electrode of MOSFET 12 is grounded. The output voltage Vout is tapped at the connection node of MOSFET 10 and MOSFET 12. Typically, one or more schottky diodes 14 are connected in parallel with MOSFET 12 between the output node Vout and ground to minimize losses during dead time conduction period.
Half-bridge arrangements are vastly used in power supply devices. FIG. 2 schematically illustrates a conventional half-bridge arrangement in an MCM. Referring to these figures, according to a conventional arrangement, MOSFETs 10, 12 are disposed on a common circuit board 18. The circuit board 18 may be thermally conductive so that heat generated by the MOSFETs during operation may be transmitted to a heatsink (not shown) which may be placed in thermal contact with the circuit board 18. A suitable circuit board 18 may be an insulated metal substrate (IMS). As shown in FIG. 2, the drain electrode 10A, 12A, of each MOSFET 10, 12 is electrically connected to a respective conductive pad 22, 24 on substrate 18. To complete a half-bridge, source electrode 10B of MOSFET 10 is electrically connnected to drain electrode 12A of MOSFET 12 through, for example a router, source electrode 12B of MOSFET 12 is connected to ground and drain electrode 10A of MOSFET 10 is connected to a voltage source as shown schematically in FIG. 2. Optionally, as shown in FIG. 2, a schottky diode 14 may be connected across drain electrode 12A and source electrode 12B of MOSFET 12 as is well known in the art.